fix(ops-backend/service-station): close Phase 19 KEEP-VERIFY — 25 defects (unreachable announcements + station write privilege escalation; banner 500 + soft-delete leak; content publish dead-end; program approval dead-end/draft leak/zero counts/missing withdraw; zero-coverage test schema) ; add V042 announcement chain + 34 guard tests; full regression 602 green

Backend
- Service Station: expose the 「临时公告」 chain end-to-end (V042 table/service existed
  but had ZERO endpoints -> both admin and miniapp could never reach it): 5 operator
  endpoints (list/create/update/publish/archive) + 1 user-facing read endpoint.
- Fix privilege escalation: create/update were guarded only by the class-level
  service_location.view, making V015's service_location.manage a never-used dead
  permission -> read-only roles could edit stations. Permissions moved to method level.
- Add ServiceLocationOperatorController to OperatorEndpointPermissionCoverageTest
  (it was NOT scanned, which is why the escalation stayed invisible).
- Add create/update validation (address NOT NULL + status CHECK only blew up on PG).
- Banner: validation failures threw bare RuntimeException -> 500; now VALIDATION_ERROR
  -> 400. Add deleted_at IS NULL to both home queries (soft-deleted banners stayed live).
- Content: operator list/detail split (admin «publish» was a dead end because it reused
  the published-only public API); category deactivate/reactivate; article body on edit.
- Service Program: operator member list now includes pending (approval reachable);
  active-only public visibility (draft leak); memberCount/pendingCount aggregation;
  withdraw/removeMember; reuse row on re-apply (UNIQUE(program_id,user_id) crash).
- MeController: add the missing GET /me/service-history route.

Schema / guards
- schema-h2.sql: add service_location_announcements (+ chk_announcement_status) and
  content_categories (+ uk_content_category_code, chk_category_status); move both into
  REQUIRED_IN_TEST_SCHEMA. MigrationValidationTest baseline 41 -> 42.
- V11PermissionMatrixContractTest now scans ALL migrations instead of hardcoding V015+V029.
- New: ServiceLocationAnnouncementPhase19IntegrationTest (24),
  ServiceLocationControllerPermissionContractTest (5),
  ServiceLocationAnnouncementConstraintParityTest (5, prod DDL <-> test schema <->
  backend whitelist <-> admin labels).

Frontend
- admin-web: ServiceStationView gains announcement management (statuses, create/edit,
  publish/archive with confirm, expiry); write buttons gated by service_location.manage.
- miniapp: U50 renders the 临时公告 block via new serviceStationService; page no longer
  talks to utils/api directly; announcement failure degrades to [] instead of erroring.
- ui-tests: U37 four-group + U50 announcement contracts; /home assertion retargeted to
  the service layer.

Verification
- Negative verification: 3 injected defects (drop soft-delete filter / drop test-schema
  CHECK / downgrade write endpoint to view) -> 4 named tests fail precisely, no
  collateral failures; restored, NEG-VAL residue = 0.
- Backend full regression: 602 tests, 0 failures, 0 errors, 3 skipped (baseline 420).
- admin-web: vue-tsc --noEmit EXIT=0, vite build EXIT=0. Miniapp: tsc --noEmit EXIT=0.
- ui-tests 14/14 PASS.

miniapp/pages/service-station/service-station.wxml

@@ -13,6 +13,22 @@
         <view class="station-info-row"><image src="/assets/icons/home/activity.png" mode="aspectFit" /><view><text class="station-info-label">开放时间</text><text class="station-info-value">{{serviceLocation.openingHoursText || '以平台通知为准'}}</text></view></view>
       </view>
 
+      <view class="block" wx:if="{{announcements.length}}">
+        <text class="block-title">临时公告</text>
+        <view class="station-announcements">
+          <view
+            wx:for="{{announcements}}"
+            wx:key="id"
+            class="station-announcement"
+            data-id="{{item.id}}"
+            bindtap="onShowAnnouncement"
+          >
+            <view class="station-announcement-head"><text class="station-announcement-dot"></text><text class="station-announcement-title">{{item.title}}</text></view>
+            <text class="station-announcement-body">{{item.content || item.title}}</text>
+          </view>
+        </view>
+      </view>
+
       <view class="block"><text class="block-title">服务项目</text><view class="station-services"><view wx:for="{{serviceLocation.services}}" wx:key="*this" class="station-service"><image src="/assets/icons/home/matchmaker.png" mode="aspectFit" /><text>{{item}}</text></view></view></view>
 
       <view class="privacy-note"><image src="/assets/icons/home/anti-fraud.png" mode="aspectFit" /><text>服务站人员仅处理现场预约与指定服务，不会浏览无关用户资料。</text></view>